drivers/nvdimm/blk.c

   1 /*
   2  * NVDIMM Block Window Driver
   3  * Copyright (c) 2014, Intel Corporation.
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms and conditions of the GNU General Public License,
   7  * version 2, as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12  * more details.
  13  */
  14
  15 #include <linux/blkdev.h>
  16 #include <linux/fs.h>
  17 #include <linux/genhd.h>
  18 #include <linux/module.h>
  19 #include <linux/moduleparam.h>
  20 #include <linux/nd.h>
  21 #include <linux/sizes.h>
  22 #include "nd.h"
  23
  24 struct nd_blk_device {
  25         struct request_queue *queue;
  26         struct gendisk *disk;
  27         struct nd_namespace_blk *nsblk;
  28         struct nd_blk_region *ndbr;
  29         size_t disk_size;
  30 };
  31
  32 static int nd_blk_major;
  33
  34 static resource_size_t to_dev_offset(struct nd_namespace_blk *nsblk,
  35                                 resource_size_t ns_offset, unsigned int len)
  36 {
  37         int i;
  38
  39         for (i = 0; i < nsblk->num_resources; i++) {
  40                 if (ns_offset < resource_size(nsblk->res[i])) {
  41                         if (ns_offset + len > resource_size(nsblk->res[i])) {
  42                                 dev_WARN_ONCE(&nsblk->common.dev, 1,
  43                                         "illegal request\n");
  44                                 return SIZE_MAX;
  45                         }
  46                         return nsblk->res[i]->start + ns_offset;
  47                 }
  48                 ns_offset -= resource_size(nsblk->res[i]);
  49         }
  50
  51         dev_WARN_ONCE(&nsblk->common.dev, 1, "request out of range\n");
  52         return SIZE_MAX;
  53 }
  54
  55 static void nd_blk_make_request(struct request_queue *q, struct bio *bio)
  56 {
  57         struct block_device *bdev = bio->bi_bdev;
  58         struct gendisk *disk = bdev->bd_disk;
  59         struct nd_namespace_blk *nsblk;
  60         struct nd_blk_device *blk_dev;
  61         struct nd_blk_region *ndbr;
  62         struct bvec_iter iter;
  63         struct bio_vec bvec;
  64         int err = 0, rw;
  65
  66         blk_dev = disk->private_data;
  67         nsblk = blk_dev->nsblk;
  68         ndbr = blk_dev->ndbr;
  69         rw = bio_data_dir(bio);
  70         bio_for_each_segment(bvec, bio, iter) {
  71                 unsigned int len = bvec.bv_len;
  72                 resource_size_t dev_offset;
  73                 void *iobuf;
  74
  75                 BUG_ON(len > PAGE_SIZE);
  76
  77                 dev_offset = to_dev_offset(nsblk,
  78                                 iter.bi_sector << SECTOR_SHIFT, len);
  79                 if (dev_offset == SIZE_MAX) {
  80                         err = -EIO;
  81                         goto out;
  82                 }
  83
  84                 iobuf = kmap_atomic(bvec.bv_page);
  85                 err = ndbr->do_io(ndbr, dev_offset, iobuf + bvec.bv_offset,
  86                                 len, rw);
  87                 kunmap_atomic(iobuf);
  88                 if (err)
  89                         goto out;
  90         }
  91
  92  out:
  93         bio_endio(bio, err);
  94 }
  95
  96 static int nd_blk_rw_bytes(struct nd_namespace_common *ndns,
  97                 resource_size_t offset, void *iobuf, size_t n, int rw)
  98 {
  99         struct nd_blk_device *blk_dev = dev_get_drvdata(ndns->claim);
 100         struct nd_namespace_blk *nsblk = blk_dev->nsblk;
 101         struct nd_blk_region *ndbr = blk_dev->ndbr;
 102         resource_size_t dev_offset;
 103
 104         dev_offset = to_dev_offset(nsblk, offset, n);
 105
 106         if (unlikely(offset + n > blk_dev->disk_size)) {
 107                 dev_WARN_ONCE(&ndns->dev, 1, "request out of range\n");
 108                 return -EFAULT;
 109         }
 110
 111         if (dev_offset == SIZE_MAX)
 112                 return -EIO;
 113
 114         return ndbr->do_io(ndbr, dev_offset, iobuf, n, rw);
 115 }
 116
 117 static const struct block_device_operations nd_blk_fops = {
 118         .owner = THIS_MODULE,
 119 };
 120
 121 static int nd_blk_attach_disk(struct nd_namespace_common *ndns,
 122                 struct nd_blk_device *blk_dev)
 123 {
 124         struct nd_namespace_blk *nsblk = to_nd_namespace_blk(&ndns->dev);
 125         struct gendisk *disk;
 126
 127         blk_dev->queue = blk_alloc_queue(GFP_KERNEL);
 128         if (!blk_dev->queue)
 129                 return -ENOMEM;
 130
 131         blk_queue_make_request(blk_dev->queue, nd_blk_make_request);
 132         blk_queue_max_hw_sectors(blk_dev->queue, UINT_MAX);
 133         blk_queue_bounce_limit(blk_dev->queue, BLK_BOUNCE_ANY);
 134         blk_queue_logical_block_size(blk_dev->queue, nsblk->lbasize);
 135         queue_flag_set_unlocked(QUEUE_FLAG_NONROT, blk_dev->queue);
 136
 137         disk = blk_dev->disk = alloc_disk(0);
 138         if (!disk) {
 139                 blk_cleanup_queue(blk_dev->queue);
 140                 return -ENOMEM;
 141         }
 142
 143         disk->driverfs_dev      = &ndns->dev;
 144         disk->major             = nd_blk_major;
 145         disk->first_minor       = 0;
 146         disk->fops              = &nd_blk_fops;
 147         disk->private_data      = blk_dev;
 148         disk->queue             = blk_dev->queue;
 149         disk->flags             = GENHD_FL_EXT_DEVT;
 150         nvdimm_namespace_disk_name(ndns, disk->disk_name);
 151         set_capacity(disk, blk_dev->disk_size >> SECTOR_SHIFT);
 152         add_disk(disk);
 153
 154         return 0;
 155 }
 156
 157 static int nd_blk_probe(struct device *dev)
 158 {
 159         struct nd_namespace_common *ndns;
 160         struct nd_blk_device *blk_dev;
 161         int rc;
 162
 163         ndns = nvdimm_namespace_common_probe(dev);
 164         if (IS_ERR(ndns))
 165                 return PTR_ERR(ndns);
 166
 167         blk_dev = kzalloc(sizeof(*blk_dev), GFP_KERNEL);
 168         if (!blk_dev)
 169                 return -ENOMEM;
 170
 171         blk_dev->disk_size = nvdimm_namespace_capacity(ndns);
 172         blk_dev->ndbr = to_nd_blk_region(dev->parent);
 173         blk_dev->nsblk = to_nd_namespace_blk(&ndns->dev);
 174         dev_set_drvdata(dev, blk_dev);
 175
 176         ndns->rw_bytes = nd_blk_rw_bytes;
 177         if (is_nd_btt(dev))
 178                 rc = nvdimm_namespace_attach_btt(ndns);
 179         else if (nd_btt_probe(ndns, blk_dev) == 0) {
 180                 /* we'll come back as btt-blk */
 181                 rc = -ENXIO;
 182         } else
 183                 rc = nd_blk_attach_disk(ndns, blk_dev);
 184         if (rc)
 185                 kfree(blk_dev);
 186         return rc;
 187 }
 188
 189 static void nd_blk_detach_disk(struct nd_blk_device *blk_dev)
 190 {
 191         del_gendisk(blk_dev->disk);
 192         put_disk(blk_dev->disk);
 193         blk_cleanup_queue(blk_dev->queue);
 194 }
 195
 196 static int nd_blk_remove(struct device *dev)
 197 {
 198         struct nd_blk_device *blk_dev = dev_get_drvdata(dev);
 199
 200         if (is_nd_btt(dev))
 201                 nvdimm_namespace_detach_btt(to_nd_btt(dev)->ndns);
 202         else
 203                 nd_blk_detach_disk(blk_dev);
 204         kfree(blk_dev);
 205
 206         return 0;
 207 }
 208
 209 static struct nd_device_driver nd_blk_driver = {
 210         .probe = nd_blk_probe,
 211         .remove = nd_blk_remove,
 212         .drv = {
 213                 .name = "nd_blk",
 214         },
 215         .type = ND_DRIVER_NAMESPACE_BLK,
 216 };
 217
 218 static int __init nd_blk_init(void)
 219 {
 220         int rc;
 221
 222         rc = register_blkdev(0, "nd_blk");
 223         if (rc < 0)
 224                 return rc;
 225
 226         nd_blk_major = rc;
 227         rc = nd_driver_register(&nd_blk_driver);
 228
 229         if (rc < 0)
 230                 unregister_blkdev(nd_blk_major, "nd_blk");
 231
 232         return rc;
 233 }
 234
 235 static void __exit nd_blk_exit(void)
 236 {
 237         driver_unregister(&nd_blk_driver.drv);
 238         unregister_blkdev(nd_blk_major, "nd_blk");
 239 }
 240
 241 MODULE_AUTHOR("Ross Zwisler <ross.zwisler@linux.intel.com>");
 242 MODULE_LICENSE("GPL v2");
 243 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_BLK);
 244 module_init(nd_blk_init);
 245 module_exit(nd_blk_exit);